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Confusion - a12/a15 heads

Posted: Thu May 29, 2014 10:09 pm
by twin120ys
Hi guys

on my a12, it has an unusual bolt pattern for the carb manifold (pictured). I think this is an a15 head as ive see this on some before.

All of my other manifolds have a whole in the center to bolt to head whereas this has two either side?

Any thoughts on what/why my a12 would have this head on it?

Cheers

Re: Confusion - a12/a15 heads

Posted: Thu May 29, 2014 10:35 pm
by classicdat
:agree:
Oval port heads as fitted to most A14-15 engines had the 2 upper studs on the inlet manifold. This is an upgrade which allows better 'flow' with having the bigger ports.

Re: Confusion - a12/a15 heads

Posted: Thu May 29, 2014 10:44 pm
by Bartman
I'm sure there was a round port head which didn't have the center bolt.
I don't know where it came from, but I once had to drill and tap that center hole to fit my round port manifold to a round port head.

Re: Confusion - a12/a15 heads

Posted: Fri May 30, 2014 9:42 am
by twin120ys
Interesting.

It is round port. Not sure whether to keep this one and try find a dellorto manifold to fit it, or to go back to a normal head?

Bartman, did you have any trouble re tapping?

Re: Confusion - a12/a15 heads

Posted: Fri May 30, 2014 5:08 pm
by Bartman
Not much.
Head was off the car though. I just measured three times, and drilled once. From memory, the hole for the stud was right over a head bolt hole. So I couldn't drill too deep.

Re: Confusion - a12/a15 heads

Posted: Sun Jun 01, 2014 8:29 am
by twin120ys
Good to know, cheers

So from what i believe, a a15 dellorto manifold would match up to this head?

Re: Confusion - a12/a15 heads

Posted: Mon Jun 09, 2014 8:05 pm
by Naki-Fisher
Yea A15 Manifold will fit, although the ports will be a miss match oval vs round.
I think some of the late model engines changed to this pattern. most of the mini stock boys re drill them so no to much of a drama.